MAST-III: a European Union R&D programme in the field of marine science and technology
OCEANS 96 MTS/IEEE Conference Proceedings. The Coastal Ocean - Prospects for the 21st Century
The third programme in marine science and technology (MAST-III) of the European Union was adopted... more The third programme in marine science and technology (MAST-III) of the European Union was adopted for the period 1994-98 with a budget of some 230 million ECU (330 million USD), of which 30% for marine technologies and some 10% for coastal engineering. A first round of projects has been funded and started early in 1996. The programme has been divided
Echo I expedition, carried out in June, 1983 using RN Melville, was funded jointly by NSF and NOA... more Echo I expedition, carried out in June, 1983 using RN Melville, was funded jointly by NSF and NOAA to carry out acoustic backscatter measurements in a manganese nodule area and to investigate the environmental impact of use ot a preliminary model ot a mining device. The site was located at 140-40'N, 1250 25'W, near DOMES site C. Data sources were the MPL Deep Tow system (primarily precision sounding, Side-looking sonar and photography) ith a newly added acoustic backscatter measuring system operating at 7 discrete frequencies between 4* and 160 kHz, and a box corer operated by R. Hessler's group. All observations and samples were tied together geographically by a sea floor acoustic transponder network. A Seabeam multibeam echo sounder survey, including quantitative measurement ot relative reflectivity of the bottom, had been made as a part ot this program just the month before. The dredge tracks were mapped with side-looking sonar and areas having differing nodule covera...
On the basis of measurements made with an experimental setup on two expeditions in the North Paci... more On the basis of measurements made with an experimental setup on two expeditions in the North Pacific, the requirements and the design of an acoustic manganese nodule survey system are discussed. The nodule coverage is deduced from the backscatter coefficients measured with specially adapted multifrequency (4.5 to 163 kHz) side looking sonars installed on a transponder navigated deep tow vehicle of the Scripps Institution of Oceanography. Special attention is given to the acoustically important aspects such as transducer beamwidths, pulse lengths, vehicle stability, three-dimensional navigation sensors, uniform patch size, data preprocessing and ship-board data processing. It is concluded that currently available technologies can be used to build an efficient multi-frequency narrow band survey system to determine the economically interesting manganese nodule areas.
Measurements of the acoustic backscatter of manganese nodules
The Journal of the Acoustical Society of America, 1985
The acoustic backscatter of eight well-curated ferromanganese nodules has been measured in 1 °C s... more The acoustic backscatter of eight well-curated ferromanganese nodules has been measured in 1 °C seawater at frequencies from 45 to 167 kHz. The nodules have diameters from 37 to 121 mm and are thought to be representative of the Cu–Ni–Co-rich nodules from the area around 14° 40′ N, 125° 25′ W (DOMES site C). They had been collected in box cores on the Echo 1 expedition and were kept refrigerated and water soaked in air-tight plastic bags. Acoustic backscatter variations of over 10 dB were observed while the nodule was rotated 10° to 30° about one of its principal axes. The complicated fine structure, as well as the target strength, makes it clear that nodules cannot be modeled as simple spheres.
The Journal of the Acoustical Society of America, 1986
U. MONITORING AGENQY NAME ft AODRESSCl/ dUlnitt Itam Controlling Offica) 13. NUMBER OF PAGES 187 ... more U. MONITORING AGENQY NAME ft AODRESSCl/ dUlnitt Itam Controlling Offica) 13. NUMBER OF PAGES 187 pages 15. SECURITY CLASS, (oi thit raporl) UNCLASSIFIED ISa. DECL ASSIFICATION/ DOWNGRADING SCHEDULE 16. DISTRIBUTION STATEMENT rol Ihia KaporO Document cleared for public release; distribution unlimited. 17. DISTRIBUTION STATEMENT (ot th» abttrmct tttmrmd In Block 30, It dllfarmt Iron Raport) IB. SUPPLEMENTARY NOTES 19. KEY WORDS CConllnua on nvatta alda It naeaaauy and Idantity by black numbar) acoustic backscatter, deep tow, manganese nodule, Patton Escarpment 20. ABSTRACT (Conllnua on ravaraa alda II naeamaary and Idantity by block numbar) In 1983 in area of Cu-Ni rich manganese nodules at 14°40'N, 126°25'W (site 'E') was intensively studied with the Deep-Tow of the Scripps Institution of Oceanography, and 16 box cores were collected. Deep-Tow studies of the Thirtymile-Bank off the California Coast and the deep sea at the foot of the Patton Escarpment followed. The nodule coverage at site 'E" varies from 0% to 80%. The nodule sizes vary between 1 and 13 cm. The nodule size distributions are best modeled by a Gaussian distribution. The three main DO , :2:"7, 1473 EDITION OF 1 HOV <8 IS OBSOLETE S/N 0102-LF-014-6601 SECURITY CLASSIFICATION OF THIS PAGE (Whan Data Bntarad) SeCumTY CLASSiriCATtON or THIS PAGC rWhM Data bMr*4 nodule axes are related to each other at 1:0.8:0.5. The average density of individual nodules is 2.0 ±0.04 g/cm3 and the volumes increase on the average with the 2.8 power of the third root of the product of the three radii. Changes of the thickness of the upper acoustic unit of the sediment column correlate with changes in nodule coverage and concentration. The acoustic backscatter has been measured for frequencies of 4.5, 9, 15, 28, 50, 112 and 163 kHz and grazing angles from normal incidence to 5. The backscatter increases as the square of the frequency for sediments. Theibackscatter of the deep sea sediments at the foot of the Patton escarpment exceeds the backscatter of the sediments at site 'E' by several dB (depending on the frequency and on the grazing angle). The backscatter from manganese nodules depends on the nodule coverage and on the frequency and exceeds that of sediments, but is less than that from the Thirtymile-Bank phosphorites. In nodule fields the backscatter comes at normal incidence from the first Fresnel zone for frequencies from 4.5 to 60 kHz and increases as the square of the coverage. The width and the asymmetry of the covariance change when the nodule coverage changes, A computer model with ellipsoidal targets relates the backscatter to the target strengths of the nodules and reproduces the covariance. It is concluded that it is possible to distinguish acoustically between different deep sea sediment types and to assess manganese nodule resources. The optimal frequencies are between 15 and 60 kHz.
Variability of acoustic reflectivity over a manganese nodule field
The Journal of the Acoustical Society of America, 1983
The backscattering from a manganese nodule field is studied. The theory predicts a dependence of ... more The backscattering from a manganese nodule field is studied. The theory predicts a dependence of reflectivity on acoustic wavelength, nodule shape, nodule size and number of nodules per unit area. First results from a recent deep tow expedition (ECHO Leg 01, June 1983) are presented. The variability of reflectivity with nodule coverage and size is discussed for each of several frequencies (4.5, 9, 28, 60, 110, 163 kHz). The acoustic data, obtained some 70 m above the deep sea floor, are compared with bottom photographs and box cores taken along the same path.
The Journal of the Acoustical Society of America, 1990
On the expeditions Echo 1 and Echo 2 the acoustic backscatter from four different seafloor enviro... more On the expeditions Echo 1 and Echo 2 the acoustic backscatter from four different seafloor environments was measured at frequencies of 4.5, 9, 15, 28, 60, 112, and 163 kHz and grazing angles from 5–90 deg. Five transducer arrays had been mounted on the stern of the Deep Tow vehicle of the Scripps Institution of Oceanography, similar sidescan sonars, but looking aft. At frequencies above 15 kHz the backscattering strength increases as one goes from deep-sea clay (14 °N, 126 °W) to silty clay (Patton Escarpment), manganese nodules (14 °N,126 °W), and phosphorite nodules and slabs (Thirtymile Bank). This order was found to be preserved at all grazing angles. It is thus possible to distinguish acoustically between the four environments. Detailed studies of the backscattered sound over the nodule field have shown that the returned energy is coherent at normal incidence, while at other grazing angles it is not. At frequencies above 15 kHz it is possible to deduce the percentage of seafloo...
Science-policy integration is one of the most complex challenges that scientific and policy-makin... more Science-policy integration is one of the most complex challenges that scientific and policy-making communities are facing in that it involves knowledge sharing and exchanges among a wide range of disciplines and actors. In many instances, the lack of communication and of clear coordination mechanism leads to research outputs not being used or simply known by policy-makers, and to policy research needs not being communicated to the scientific communities in a timely fashion. This paper discusses the integration of scientific and technological progress into the policy-making and implementation process, taking the European Union Water Framework Directive (WFD) as an example to illustrate the necessity and complexity of the knowledge-based approach.
The Journal of the Acoustical Society of America, 1987
The absorption and speed of sound were measured between two bore holes each 150 m deep and spaced... more The absorption and speed of sound were measured between two bore holes each 150 m deep and spaced 4 m apart. Sediment profile samples have been obtained from the two wells and the water content, porosity, density, and mineralogy determined. Acoustic measurements were made at selected depths in the water saturated sediments down to a maximum of −83 m. The acoustic frequencies ranged from 7.5–18 kHz; at the lower frequency, the absorption varied from 0.3 dB/m in clay to 0.4 dB/m in sand. At 18 kHz the corresponding values were 2.0 and 4.5 dB/m, respectively. Measurements of sound speeds for clay resulted in a velocity of 1480 + 15 m/s, 1540–1820 + 15 m/s in silt, and 1540 + 15 m/s for sand, at a temperature of 12 °C. The absorption measurements compare well at 12 kHz to those made in late 1986 in deep ocean sediments using penetrators that were able to penetrate up to 55 m into the sediments.
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